Time is running out for freshwater dolphins say experts

06 July 2000 | News story

Gland, Switzerland (IUCN) 06.07.2000. IUCN - The World Conservation Union is calling on governments, conservation organisations and journalists to support urgent international efforts to save a number of species of river dolphins and a species of porpoise which are facing imminent extinction.

River dolphins and the Yangtze finless porpoise (collectively know as freshwater cetaceans) are among the world's most endangered mammals. Dolphins inhabit several large rivers of southern Asia but populations have declined dramatically in recent years. Construction of dams, irrigation, flood control, and hydroelectric projects to service a rapidly expanding human population in the region has had disastrous effects on these animals. River dolphins also occur in South America but are not considered as endangered as their Asian relatives.

Accidental killing through collision with boats, entanglement in fishing equipment, loss of quality habitat, reduced food supplies through over-fishing, pollution, and fragmentation of populations and reduced suitability of natural habitat through dam construction are among the threats driving these species towards extinction. Some river dolphins are still hunted for their oil which is used to attract fish, for their meat, and for use in medicines.

Much needed attention was focused on freshwater cetaceans during the recent meeting of the Scientific Committee of the International Whaling Commission (IWC) in Adelaide, Australia.

The meeting endorsed recommendations made by experts of IUCN's Species Survival Commission (a global network of some 7,000 scientists, researchers and conservation practitioners). The SSC's Cetacean Specialist Group has treated freshwater and coastal small cetaceans as its highest priority for the last 15 years. Much has been learned about where the animals occur, the threats they face and how many there are, but very little progress has been made in improving their chances for survival.

The discussions in Adelaide came soon after the release of an SSC publication Biology and Conservation of Freshwater Cetaceans in Asia. This brings together current information on the status of Asian river cetaceans, the threats that have caused their decline and what can be done to help save them. All of the species or populations featured in the volume are classified by IUCN as Endangered or Critically Endangered.

Undoubtedly the most endangered cetacean worldwide is the baiji (Lipotes vexillifer). It occurs in China's heavily polluted Yangtze River where only a few tens of individuals remain. A last-ditch effort to capture the remaining animals and move them into a semi-natural reserve failed and there is little hope for the survival of the species. Yet the baiji is deemed a 'national treasure' in China and rivals the giant panda as an animal deserving protection of its fragile habitat.

Also of grave concern is the Yangtze population of the finless porpoise (Neophocaena phocaenoides). This is the world's only freshwater-adapted population of porpoises, and is reported to be declining rapidly. Finless porpoises occur in a coastal band around continental Asia from Japan to the Persian Gulf yet in areas of Japan's Inland Sea they have declined by some 95% since the 1970s.

Two closely related river dolphins of the Asian subcontinent, one in the Indus (Platanista gangetica minor) and one in the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu (Platanista gangetica gangetica), and freshwater populations of Irrawaddy dolphins (Orcaella brevirostris) in the Mekong, Mahakam, and Irrawaddy Rivers, as well as populations in brackish waters of Sonkhla (Thailand) and Chilka (India) lakes, are also highly threatened.

The IWC Scientific Committee made a range of recommendations. These include: a thorough investigation of the impacts of water development projects on freshwater cetaceans and measures to ensure that ongoing and future projects do not further endanger these animals; an assessment of the scale of accidental catch and the implementation of strategies to reduce this threat; an evaluation of the effects of pollutants such as pesticides, mercury and oil on river cetaceans; and an improvement in survey methods to gain a more accurate picture of how many animals are left.

The committee also urged that the IWC Secretary ask the Government of China to report annually on progress made in the conservation of the baiji.

"The deteriorating status of Asia's freshwater cetaceans is one of the most urgent species conservation problems facing the world today. Its causes are partly local and related to the fact that growing human populations are competing with the animals for water and other resources. But the international community is also implicated through its support for projects that ignore the fragility, complexity and vitality of natural freshwater systems. Some of the range states are trying hard to save these species and their habitat, but they are quickly running out of time," says Randall Reeves, chair of the Cetacean Specialist Group.